This invention relates to an apparatus for manufacturing labels for electronic article surveillance. The label comprises a label repositioner which by means of a first dispensing edge removes the labels from a carrier web and by means of a second dispensing edge places them in a predetermined position on the same or a different carrier web. The present invention also relates to an applicator unit for applying security elements to the carrier web. Furthermore, the invention and to a method for manufacturing labels for electronic article surveillance.
From Published International Application WO 97/14126 there is already known a method and an apparatus for combining security elements with labels. After the labels are delaminated from the carrier web, the web is guided in a loop around the delaminating station. Then the labels are put back onto the same carrier web at a predetermined relative distance.
Within the loop formed by the carrier web, security elements are placed in succession on the carrier web so that later they lie between the repositioned labels and the carrier web. The security elements are applied to the carrier web intermittently by means of a dispensing edge. The security elements are pressed onto the carrier web preferably by means of blast air. A disadvantage of the known apparatus is its relatively low speed of production due to the intermittent operating mode of the blast air applicators.
It should be noted that a further apparatus for incorporating security elements in a strip of labels is also known from German Patent DE 44 36 284 A1.
It is an object of the present invention to provide an apparatus and a method with which the production of labels for electronic article surveillance can be accelerated.
With respect to the apparatus, this object is accomplished in that the applicator unit is constructed to apply the security elements continuously to the carrier web, whereby at least one security element is allocated to each label or to any number of labels. The solution of the present invention enables the production process to be accelerated at will because a continuous application of the security elements to the carrier web, onto which the labels are subsequently placed, likewise continuously, can be performed substantially more quickly and easily than an intermittent feeding involving a step by step movement of the carrier web to the next position.
It is possible, of course, to use all the known types of security element, for example, soft magnetic security elements, resonant frequency security elements, acousto-magnetic security elements etc., as security elements. To enable the labels to be delaminated from the carrier web without difficulty, the adhesive force between the adhesive material and the labels is greater than the adhesive force between the adhesive material and the carrier web.
According to an advantageous further aspect of the apparatus of this invention, the applicator unit is comprised of the following sub-elements: an application cylinder, on which the security elements are fixed by vacuum or magnets, and a further applicator.
While a vacuum application cylinder can be used completely irrespectively of the nature of the security elements needing to be dispensed, it will be obvious that an application cylinder based on magnetic attraction is suitable only for applying magnetic security elements.
Considering that it should be possible to use the apparatus according to the present invention for the application of security elements and labels of completely different dimensions, a favorable aspect provides for a regulating/controlling device which guarantees that the security elements are positioned correctly in relation to the labels. The apparatus should also be able in particular to equip not every label but only a selected number of labels with security elements. For example, it is desirable that the apparatus be able to equip only every fourth label on a strip of labels with a security element. An accordingly designed label strip is already described in European Patent EP 0 682 333 A1.
A preferred aspect of the apparatus of the present invention provides for the applicator to be comprised of the following sub-elements: a supply roll on which a carrier web supporting the security elements is wound, a dispensing edge over which the security elements are transferred to the application cylinder, and at least one sensor which detects the relative distance of the individual security elements and their length.
To enable the security elements to be readily applied to the application cylinder, provision is made for an adhesive between the carrier web and the security elements whose adhesive force relative to the carrier web is smaller than the force of attraction/suction exerted by the application cylinder on the security elements. It is also possible, of course, to construct the apparatus of the present invention in such a way as to enable several labels arranged side by side on the carrier web to be equipped simultaneously with security elements. This simply requires the corresponding cylinders to be suitably dimensioned.
In an advantageous further aspect of the apparatus of the present invention, a first sensor is proposed which detects the relative distance of the labels on the carrier web; a second sensor detects the relative distance of the security elements on the carrier web, while a third sensor is assigned to the application cylinder and detects the relative distance of the security elements fixed on the application cylinder. This data is made available to the controlling/regulating device which can use it to set the relative speed between the speed at which the security elements are fed by the applicator unit and the peripheral speed of the application cylinder so that the security elements are applied to any desired point on the application cylinder and subsequently to the carrier web. Hence it is possible for any number of labels to be equipped exactly with at least one security element. Furthermore, provision is made in particular for the controlling/regulating device to adapt the peripheral speed of the application cylinder to the running speed of the carrier web.
Still further, the controlling/regulating device sets the peripheral speed of the applicator""s supply roll so that the security elements are put on the application cylinder at a desired relative distance and are then transferred to the carrier web to be subsequently positioned under the desired number of labels.
The supply roll and the application cylinder are each allocated an angle transmitter and a motor to enable them to be controlled correctly.
If, at an identical speed of application cylinder and carrier web, the measurement values supplied by the sensors indicate that corrections have to be made to the position of the security elements in relation to the carrier web, the controlling/regulating device will vary the peripheral speed of the application cylinder accordingly so that the security elements on the application cylinder have the predetermined relative distance. Accordingly, after carrier web and labels are laminated together, the security elements are again positioned under the desired number of labels in the predetermined area of a label.
As regards the method for manufacturing labels for electronic article surveillance, the object of the present invention is accomplished as follows: the labels are removed from the carrier web by means of a first dispensing edge and put back onto the same or a different carrier web in a predetermined position by means of a second dispensing edge; the security elements are removed from a second carrier web by means of a further dispensing edge and transferred continuously by an application cylinder to the first carrier web so that, after carrier web and labels are laminated together, at least one security element is allocated to a desired number of labels.
The present invention will be explained in more detail in the following with reference to the accompanying drawing.